1. Field of the Invention
This invention is for use in connection with a land irrigation system in which a moving water sprinkler line having a water inlet at one point extends laterally to and moves along the length dimension of a stationary water supply main having a plurality of water outlet valves at equally spaced points along its length, and particularly involves an apparatus including automatic coupling means for successively connecting the water outlet valves with water inlet means of the sprinkler line, the apparatus including a driven conveyance means for moving along the length dimension of the stationary water supply main at substantially the same overall rate of movement as the moving sprinkler line.
This invention is also useful in connection with a method of land irrigation wherein a moving sprinkler line having a water inlet at one point moves along the length of a stationary water supply main having water outlet valves in hydrants located at spaced intervals along the length thereof, the method involving the use of automatic coupling means for successively connecting the water outlet valves with water inlet means of the sprinkler line to obtain a substantially continuous water supply to the sprinkler line.
2. Description of the Prior Art
When irrigating extensive areas of land, long sprinkler lines have been used for some time. Water has been supplied to these lines from buried pipes or mains having spaced risers projecting above the surface of the ground for connection to the sprinkler lines. Initially each time a sprinkler line had to be moved, manual labor was required for this purpose. This was a laborious and time consuming operation. At time went on, the sprinkler lines, which can reach a length of a quarter of a mile and more were fitted with wheels to make them easier to move. Eventually, power was supplied in one way or another to the wheeled lines to keep them moving slowly along the desired path parallel to the direction of the main line, with flexible hoses extending between the water inlet end of the sprinkler lines and the riser to which the sprinkler line was connected. Since the mains can be eight or more inches in diameter and contain water under substantial pressure, the required size and strength of the flexible hoses became extremely burdensome in manual operation. Proposals were therefore made to facilitate connection of the sprinkling lines to successive risers with the least manual effort but it is not believed that a successful machine has previously been developed. Examples of such proposals are illustrated in Engel U.S. Pat. No. 2,750,228, Stafford U.S. Pat. No. Re. 26,285 and Smith et al U.S. Pat. Nos. 3,381,893 and 3,446,434. Such proposals provided for intermittent connection of the sprinkler line to the main line utilizing power assisted mechanical devices as the hoses or telescoping pipes were moved from riser to riser, with the sprinkler line continuing to move along at the desired rate.
In order to provide for a continual source of water to the sprinkler line Rogers U.S. Pat. No. 3,463,175, Standal U.S. Pat. No. 4,036,436, and Russian Pat. No. 434,918 proposed systems in which one riser is always connected to the sprinkler line, this being accomplished by having pipe or hose connections to the sprinkler line connect with devices which span three risers. By the arrangement employed in the Rogers and Standal patents, the forward part of the device is disconnected from a first riser and goes on to a second riser ahead of the first riser and, upon connection of the device with the second riser, the hindmost part of the device is disconnected from a third riser which is behind the first riser in the main lines moves up to and is connected with the first riser. The requirement for closely spaced risers and the unavailability of reliable water valve connecting and operating means may have contributed to the failure of these systems to have gained wide-spread commercial acceptance.
In the Russian patent, an elongated horizontal pipe having water valve connecting means at each end is pivotally mounted at its center by a downturned ell on the forward end of a second, forwardly projecting elongated horizontal pipe which, in turn, is pivotally mounted at its rear end by an upturned ell to a sprinkler line carried by a mobile carriage. The carriage moves along a water main so that when the valve connecting means on one end of the first pipe is connected to a hydrant valve, the doubly pivoted mounting permits the other end of the first pipe to swing in an arc around the hydrant to bring the other valve connecting means into position to be connected to a second hydrant valve (apparently manually) before the first is disconnected. The entire water connecting means is, therefore, cantilevered forward of the carriage. Although the illustrated structure could be modified so as to be theoretically operable, the inoperability of the structure illustrated suggests that this device also may have never been actually used.
Von Linsowe U.S. Pat. No. 3,729,016 discloses another irrigation system for continuously feeding water to a sprinkler line, but this system is extremely complicated and requires twin main lines since the twin coupling devices for connecting the sprinkler line to the main line cannot pass each other. This proposal appears to have the same history in practice as the systems of the Rogers and Standal patents mentioned above.